The present invention relates to a lubricating oil composition serving as a sliding surface oil and a metal working oil, and a method of lubricating working machinery using the lubricating oil composition.
A variety of lubricating oils having different characteristics are used in working machinery depending on the application part and the purpose of use. When, however, these lubricating oils intermingle with each other, there is a danger of reduction in their lubricating characteristics and occurrence of a fatal problem. Thus such intermingling is absolutely necessary to avoid.
In many working machines, particularly a transfer machine, however, a sliding surface oil often intermingles with a metal working oil such as a cutting oil and a grinding oil. In this case, if the metal working oil is of the aqueous emulsion type, the following problems arise.
(1) The metal working oil loses its uniformity in lubricating properties. For this reason, its metal working performance varies and it becomes impossible to accomplish high accuracy metal working.
(2) Decomposition is accelerated, and the service life of the metal working liquid is seriously reduced.
It has therefore been desired to overcome the above problems. As a result of extensive investigations, it has been found that a lubricating oil composition having a specified formulation can serve as a sliding surface oil, that is, an oil for lubricating a sliding surface and also as a metal working oil.